And he has insisted he had no intention of taking up the ISG’s recommendation that Israel should open peace talks with Syria.

The study group – headed by ex-Secretary of State James Baker – also said Iran and Syria should be included in talks over the way forward.

Mr Blair – who pressed that option when he gave evidence to the ISG – said Iran would first have to stop funding and supporting terrorists in Iraq.

But the US President went further, insisting Tehran would also have to first end its uranium enrichment programme.

Mr Blair said there was no doubt the situation in Iraq was “hugely challenging” but pointed out the report had not said we should “just get out”.

“It’s practical and it’s clear and it offers a way of bringing people together,” he said of the report.

“The essential elements were getting the Iraqi government to operate effectively in a non-sectarian way, making sure everyone in the region was supporting that effort and setting it in a broader Middle East context.

“In respect of the elements of that strategy this report gives us a basis on which we can move forward,” Mr Blair said.

“We have also then got to look at the practical measures that are necessary in order to give effect to those elements.”

An angry Mr Bush rejected suggestions he was underestimating the scale of the challenge in Iraq.

“It’s bad in Iraq,” he said bluntly.

“Make no mistake about it, I understand how tough it is, sir. I talk to the families who die. I understand the sectarian violence.

“I have made it abundantly clear how tough it is. I also believe we’re going to succeed – I believe we’re going to prevail.

“But I also want the American people to understand that.. if we were to fail, that failed policy will come to hurt generations of Americans in the future.”

He added: “The report did a good job of showing what is possible. Congress is not going to accept every recommendation and neither will the administration.